• Translates to ‘Spiny Skin’
  • sea stars and urchins
  • slow moving and marine
  • adult = radial, larval = bilateral

• Thin epidermis covered in hard plates
  • often with bumps or spines

• Translates to ‘Spiny Skin’
  • sea stars and urchins
  • slow moving and marine
  • adult = radial, larval = bilateral

• Thin epidermis covered in hard plates
  • often with bumps or spines

• Possess a unique water vascular system
  • flexible hydraulic canals = tube feet

• All chordates share 4 traits
• Some only in embryo stages

1. Notochord
2. Dorsal, hollow nerve cord
3. Pharyngeal slits
4. Muscular, Post-anal tail

• 2 invertebrates groups that are more related to vertebrates
  • Cephlachordata (lancelets)
  • Urochordates (tunicates)

• Possess skeletal and nervous systems
  • simple to complex backbones
  • lots of unique genes (eg. HOX)

• Derived trait = neural crest
  • special cells near neural tube in embryo
  • give rise to many vertebrate traits
  • e.g.. teeth, skull cartilage, etc

• Evolved while predators where developing
  • Cambrian period
  • Ocean origins (first 150 mya)

• Vertebrate: series of bones that make up the vertebral column
  • 57,000 species

• Vertebrates with limbs colonized land 365 mya

1. Amphibians
2. Reptiles (w/ birds)
3. Mammals

• Only members of vertebrates without jaws
  • sister group of jawless fish

• Have rudimentary backbones
  • more cartilage than bone

• Hagfish escape by releasing slime
  • researched to stop bleeding in surgery

• Only members of vertebrates without jaws
  • sister group of jawless fish

• Have rudimentary backbones
  • more cartilage than bone

• Hagfish escape by releasing slime
  • researched to stop bleeding in surgery

• Many Lamprey are parasitic on fish
  • invaded Great Lakes
  • native to Chesapeake Bay

• ‘Cartilage fishes’: skeletons mostly cartilage
  • often with calcium
  • originated 400 mya

• Streamlined body for swift swimming
  • poor maneuverability
  • near constant motion

• Birth via eggs or young develop inside mother

• Modern species diversity shrinking

• Phylogeny: large new vertebrate group with bony endoskeletion
  • fishes = aquatic groups

Add lungs/lung derivatives to phylogeny

• Important derived traits for fishes:
  • operculum:
  • swim bladder:

• Ray-finned: bony rays that support fins
  • trout, sea horses, eels

• Lobe-finned: rod-shaped bone surrounded by muscle in fins
  • lungfish, Coelacanths, earliest tetrapods

• A fish has a density of about 1.076
  • freshwater has a density of 1.0
  • saltwater has a density of 1.026

• Bone is nearly twice as dense as cartilage

• Swimming is energy expensive
  • resting on the bottom may not be practical

• Evolution of the swim bladder set fish free

• Lobe fins gradually evolved into limbs
  • Tetrapods colonized land 365 mya
  • move away from fish-like vertebrates

• Tetrapod derived trait = limbs with digits
  • supports weight
  • digits efficiently support movement

• Fossil found in river bed

• Selection of many terrestrial traits
  • head separated from body by a neck
  • add vertebrate to allow head to swing
  • bones of pelvis fuse to backbone
  • many species lost gills (became ears)

• Include salamanders, frogs and caecilians

  • 6,000 species

  • caecilians lost legs

• Rely on skin for gas exchange
  • live in moist habitats

• Name means ‘dual life’
  • some have aquatic tadpole larvae
  • more related to metamorphosis
  • gills → legs, lungs, eardrums

• Lizards, snakes, turtles, crocs and BIRDS
  • many extinct groups
  • small (16mm) to large (12m)

• Scales with keratin

• Lay shelled eggs on land

• Most reptiles are ectothermic

• Lizards, snakes, turtles, crocs and BIRDS
  • many extinct groups
  • small (16mm) to large (12m)

• Scales with keratin

• Lay shelled eggs on land

• Most reptiles are ectothermic

• Large adaptive radiation post dinosaurs
  • predators, herbivores, flying, aquatic
  • Monotremes = platypus (egg laying)
  • Maruspials = pouched mammals
  • Eutherians = placental mammals

• Derived Trait: Mammary glands
  • produce milk for offspring
    
• Derived Trait: Hair
  • insulation/water saver
    
• Derived Trait: Kidney
  • waste removing/water saving organ